This is one of the fastest growing mulberries at our farm growing more that 3-5 ft. per year. The high quality sweet fruit is not as insipid as other mulberries and is favored by people. Large lustrous green leaves are very clean and free of disease throughout the summer. The trees are resistant to witches broom which is common throughout the Midwest which deforms trees. This is the species most often cultivated for its fruit and has been widely distributed throughout the world as a fruit plant. The Pakistan varieties as well as others are only marginally hardy in Michigan if at all. I lost over a dozen varieties of them during a below minus 20 winter. Eventually I was able to create my own seed source as well as varieties from this seed source. 'Sweet Juice' provides both a varietal level selection as well as a seed source that can be grown in more northern locations.
This seed source was developed by growing out numerous seedling Morus nigra seeds that I purchased from a commercial seed house. Three distinct populations were selected including cutleaf forms and planted starting 15 years ago and continues to this day. Besides the deer issue and their love of the foliage, the yields as the tree matures are just amazing and the flavor is fantastic. This is a full zone 5 seed source of trees that could easily make other populations of this wonderful cultivated fruit.
Black mulberries contain 8 percent sugar and are high in potassium and vitamin C. This fruit is best enjoyed fresh. Trees are self fertile usually but two plants are always better than one with mulberries as trees produce male, female and perfect flowers with both parts. This cross pollination will aid in fruit set although lone trees from my farm planted elsewhere did not require it.
For years Oikos Tree Crops bought a lot of grafted black mulberries from other nurseries. Unfortunately they are not hardy at my farm. Black mulberry has a huge range in its native habitat, however most of the selection process was done in warmer climates where it rarely dips below freezing. Of course those are nice selections in warmer climates but not in Michigan and other cold regions of the U.S. above zone 7 or 8. Over time, further clonal reproduction will be done on specific selections. My focus is on large leaves, tall broad habit of growth, open tree structure and resistance to the myriad of existing mulberry diseases and of course quantities of delicious fruit. Size of fruit is not a priority but hardiness is critical in zone 5. Further selections as well as seed strains can easily be done with the groundwork done on this seed source.
Sweet Juice Vigorous tree with large leaves and strong growth habit. Fruit is produced all along the limbs in heavy clusters. Fruit ripens over a month long. The sweet tart flavor is just the right balance. Not an insipid mulberry. Delicious sweet juicy berry. The parent tree was hit with minus 25F once. The large leaves and upright rounded crown growth habit make it a nice shade tree as well. Trees can be grafted onto seedling rootstocks. The seeds from this variety also produce a zone 5 seed strain for the development of further varieties as well.
To germinate the seed: Mulberry seed has only small dormancy or none at all. If planted on the surface of the soil the seeds will sprout quickly. They do damp off easy and are loved by slugs. Provide good soil aeration for this seed. Some dormancy can be done in the refrigerator prior to sowing for 60 days at 34-38F. This will hasten and unify germination.
|Genus & Species||Morus nigra|
|Seed Source||Unknown uncultivated plants|
|Hardiness||minus 20F or more on parent trees|
|Pollination Requirements||Can be both self fertile as well as require additional pollination with another black mulberry. Generally this species is fully fertile containing both male and female flowers or complete flowers on the same plant.|
|Soil||Adaptable. Rock, clay, loam, sand.|
|Climate||Zone 5 to zone 10. Minus 20 F did not damage my seed trees.|
|Ease of Cultivation||Anyone can grow it in almost any soil and climate. No insect or disease issues. Trees fruit in 3-6 years from seed. Growth rate of 2-4 ft. per year is common. One year to establish and then you are off to the races. Different cultivars exist but hardiness is lacking in most of them as they were selections often done in warmer climates. Here black mulberry (nigra) is incredibly fast growing making it ideal as a fruit tree where little maintenance is required and the fruits are so easy to pick and use. Sweet Juice is one of only a few cultivars hardy in zone 5 and yet retains that wonderful flavor of the black mulberry.|